This invention relates to method and apparatus for classifying particles.
Various types of methods and apparatus for classifying particles have been proposed which classify fine particles according to their grain size. Among these prior art methods and apparatus, the one having the following construction can classify at a high efficiency. This type of apparatus comprises a cylindrical housing, a rotary disc including rotating classifying members mounted on the top of the cylindrical housing for classifying fine particles, means for creating a whirling upward flow of air in the cylindrical housing, means for dispersing fine particles to be classified in the upward whirling flow, and means located at the bottom of the cylindrical housing for taking out classified fine particles. With this type of apparatus, since the whole interior of the cylindrical housing is used to classify the particles according to the whirling upward flow and the gravity, fine particles can be efficiently classified according to their grain size. Such a prior art method and apparatus, however, requires independent driving mechanisms for dispersing the fine particles in the whirling upward flow and for classifying the particles, thus complicating the driving mechanism. Furthermore, disposition of various members in the cylindrical housing and movements of such members create turbulence in the classifying air which not only impairs the classifying effect but also increases the running cost.